How is the subjunctive used here in vitemus? Vitamus makes sense, but lectio difficilior suggests vitemus (iirc, some manuscripts have vitemus and some have vitamus).

Based on my browsing through Allen and Greenough, I think it is present subjunctive because it is a "General Condition," or a "general truth." I take this to mean that the stated outcome (nos . . . videmur) applies to all such situations (si . . . vitemus). So "We strong men [always] seem to do enough for the Republic, if we shun the fury and weapons of this man."